Field of the Disclosure
The present disclosure relates to a surge protection device, a method for manufacturing the same, and an electronic component including the same.
Description of the Related Art
Electro-Static Discharge (ESD) is a phenomenon of severe discharge when a charged conductive body (for example, a human body) comes into contact with or comes into close proximity to another conductive body (for example, an electronic device). ESD causes damage to or malfunction of an electronic device. Circuits of the electronic device should be protected from application of excessively high voltages resulting from the discharge so as to prevent the damage or malfunction. A surge protection device, which is also known as a surge absorbing element or a surge absorber, is used for the above-described purpose.
A surge protection device is disposed, for example, between a signal line and a ground (earth) of a circuit. Since the surge protection device has a configuration including a pair of discharge electrodes separated and opposed to each other, the surge protection device has high electrical resistance and a signal does not flow to the ground during the typical operation. However, when an excessively high voltage, for example, a voltage of static electricity from an antenna of a mobile phone or the like is applied, a discharge occurs between the discharge electrodes of the surge protection device to lead the static electricity to the ground. Accordingly, the voltage of the static electricity is not applied to the circuits downstream of the surge protection device and thus the circuits can be protected.
For example, a surge protection device illustrated in FIG. 1 has a cavity 2 formed inside of a multilayer body of a ceramic substrate 1, and includes a discharge auxiliary electrode 4 on an inner surface of the cavity 2, a pair of discharge electrodes 31 in contact with the discharge auxiliary electrode 4, and outer electrodes 32 formed on a surface of the ceramic substrate 1 and connected to the discharge electrodes 31.
The surge protection device as described above is disclosed in, for example, Patent Document 1 (International Publication No. 2008/146514) and Patent Document 2 (Japanese Unexamined Patent Application Publication No. 2010-129320). When a breakdown voltage that causes dielectric breakdown between discharge electrodes 4 is applied, a discharge occurs between the discharge electrodes 4 inside a cavity 2 and an excessively high voltage is directed to the ground. As a result, the surge protection device can protect circuits downstream of the device.
Patent Document 1: International Publication No. 2008/146514
Patent Document 2: Japanese Unexamined Patent Application Publication No. 2010-129320